System and method for simultaneous operation of multiple modems using a single transceiver

ABSTRACT

Systems and methods for simultaneously communicating over multiple air interfaces using a single transceiver are described herein. An input is received at a transceiver. The input has a first signal encoded using a first radio technology and a second signal encoded using a second radio technology. The input is converted from an analog domain to a digital domain. The input is separated into the first signal and the second signal in the digital domain.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under §119(e) to the following U.S.Provisional Applications: (1) U.S. Prov. App. No. 61/178,332, entitled“System and method for resolving conflicts between air interfaces in awireless communication system,” filed May 14, 2009; (2) U.S. Prov. App.No. 61/178,452, entitled “Allocating transmit power among multiple airinterfaces,” filed May 14, 2009; and (3) U.S. Prov. Appl. No.61/178,338, entitled “System and method for dropping and adding an airinterface in a wireless communication system,” filed May 14, 2009. Theabove-referenced applications are herein incorporated by reference intheir entirety.

BACKGROUND

1. Field

This application relates generally to communication, and morespecifically, to a receiver for a wireless communication system.

2. Background

Wireless communication systems are widely deployed to provide variouscommunication services such as voice, video, packet data, messaging,broadcast, etc. These systems may be multiple-access systems capable ofsupporting multiple users by sharing the available system resources.Examples of such multiple-access systems include Code Division MultipleAccess (CDMA) systems, Time Division Multiple Access (TDMA) systems,Frequency Division Multiple Access (FDMA) systems, Orthogonal FDMA(OFDMA) systems, and Single-Carrier FDMA (SC-FDMA) systems.

Current wireless communication systems are not optimized to communicateover multiple air interfaces (e.g., 1x, 1xAdvanced, DO, UMTS (HSPA+),GSM, GPRS, EDGE, etc.) concurrently. Thus, a need exists for wirelesscommunication systems able to concurrently communicate over multiple airinterfaces efficiently.

SUMMARY

The system, method, and devices of the invention each have severalaspects, no single one of which is solely responsible for its desirableattributes. Without limiting the scope of this invention as expressed bythe claims which follow, its more prominent features will now bediscussed briefly. After considering this discussion, and particularlyafter reading the section entitled “Detailed Description of CertainEmbodiments” one will understand how the features of this inventionprovide advantages that include concurrent communication over multipleair interfaces.

One aspect of the disclosure is a method of receiving a first inputduring a first time period, the first input comprising a first signaland a second signal, wherein the first signal is encoded using a firstradio technology and the second signal is encoded using a second radiotechnology; converting the first input from an analog domain to adigital domain; and separating the first input into the first signal andthe second signal in the digital domain.

Another aspect of this disclosure is a method of combining a firstsignal and a second signal wherein the first signal is encoded using afirst radio technology and the second signal is encoded using a secondradio technology, converting the combined signal from a digital domainto an analog domain, and transmitting the combined signal.

Another aspect of this disclosure is a wireless apparatus comprising anantenna configured to receive a first input during a first time period,the first input comprising a first signal and a second signal, whereinthe first signal is encoded using a first radio technology and thesecond signal is encoded using a second radio technology; ananalog-to-digital converter configured to convert the first input froman analog domain to a digital domain; and at least one rotatorconfigured to separate the first input into the first signal and thesecond signal in the digital domain.

Another aspect of this disclosure is a wireless apparatus comprising asummer configured to combine a first signal and a second signal whereinthe first signal is encoded using a first radio technology and thesecond signal is encoded using a second radio technology, adigital-to-analog converter configured to convert the combined signalfrom a digital domain to an analog domain, and an antenna configured totransmit the combined signal.

Another aspect of this disclosure is a wireless apparatus comprisingmeans for receiving a first input during a first time period, the firstinput comprising a first signal and a second signal, wherein the firstsignal is encoded using a first radio technology and the second signalis encoded using a second radio technology; means for converting thefirst input from an analog domain to a digital domain; and means forseparating the first input into the first signal and the second signalin the digital domain.

Another aspect of this disclosure is a wireless apparatus comprisingmeans for combining a first signal and a second signal wherein the firstsignal is encoded using a first radio technology and the second signalis encoded using a second radio technology, means for converting thecombined signal from a digital domain to an analog domain, and means fortransmitting the combined signal.

Another aspect of this disclosure is a computer program product,comprising computer-readable medium comprising code for causing acomputer to receive a first input during a first time period, the firstinput comprising a first signal and a second signal, wherein the firstsignal is encoded using a first radio technology and the second signalis encoded using a second radio technology; code for causing a computerto convert the first input from an analog domain to a digital domain;and code for causing a computer to separate the first input into thefirst signal and the second signal in the digital domain.

Another aspect of this disclosure is a computer program product,comprising computer-readable medium comprising code for causing acomputer to combine a first signal and a second signal wherein the firstsignal is encoded using a first radio technology and the second signalis encoded using a second radio technology, code for causing a computerto convert the combined signal from a digital domain to an analogdomain, and code for causing a computer to transmit the combined signal.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a diagram illustrating wireless communication devices engagedin simultaneous communication over two air interfaces.

FIG. 2 is a functional block diagram of a wireless communication device.

FIG. 3 is a functional block diagram of an exemplary receiver of awireless communication device as shown in FIG. 2.

FIG. 4 is a functional block diagram of an exemplary transmitter of awireless communication device as shown in FIG. 2.

FIG. 5 illustrates an exemplary process of receiving signals overmultiple air interfaces using the receiver as shown in FIG. 3.

FIG. 6 illustrates an exemplary process of transmitting signals overmultiple air interfaces using the transmitter as shown in FIG. 3.

FIG. 7 illustrates an exemplary transmission of multiple (N) signalsusing one or more air interfaces.

FIG. 8 illustrates encoding and/or decoding of an exemplary transmissionof multiple (N) signals using one or more air interfaces.

FIG. 9 is a flowchart of an exemplary process of recentering thetransceiver shown in FIG. 2.

FIG. 10 is a functional block diagram of another exemplary receiver of awireless communication device as shown in FIG. 2.

FIG. 11 is a functional block diagram of another exemplary transmitterof a wireless communication device as shown in FIG. 2.

DETAILED DESCRIPTION

The word “exemplary” is used herein to mean “serving as an example,instance, or illustration.” Any embodiment described herein as“exemplary” is not necessarily to be construed as preferred oradvantageous over other embodiments. The techniques described herein maybe used for various wireless communication networks such as CodeDivision Multiple Access (CDMA) networks, Time Division Multiple Access(TDMA) networks, Frequency Division Multiple Access (FDMA) networks,Orthogonal FDMA (OFDMA) networks, Single-Carrier FDMA (SC-FDMA)networks, etc. The terms “networks” and “systems” are often usedinterchangeably. The following are examples of distinct radiotechnologies that may be used with the methods and devices describedherein: various Universal Terrestrial Radio Access (UTRA) radiotechnologies, various cdma2000 radio technologies, Wideband-CDMA(W-CDMA), Low Chip Rate (LCR), IS-2000, IS-95, IS-856, Global System forMobile Communications (GSM), Evolved UTRA (E-UTRA), IEEE 802.11, IEEE802.16, IEEE 802.20, Flash-OFDM, Long Term Evolution (LTE) etc. UTRA,E-UTRA, and GSM are part of Universal Mobile Telecommunication System(UMTS). Long Term Evolution (LTE) is an upcoming release of UMTS thatuses E-UTRA. UTRA, E-UTRA, GSM, UMTS and LTE are described in documentsfrom an organization named “3rd Generation Partnership Project” (3GPP).cdma2000 is described in documents from an organization named “3rdGeneration Partnership Project 2” (3GPP2). These various radiotechnologies and standards are known in the art.

Single carrier frequency division multiple access (SC-FDMA), whichutilizes single carrier modulation and frequency domain equalization isa technique. SC-FDMA has similar performance and essentially the sameoverall complexity as those of OFDMA system. SC-FDMA signal has lowerpeak-to-average power ratio (PAPR) because of its inherent singlecarrier structure. SC-FDMA has drawn great attention, especially in theuplink communications where lower PAPR greatly benefits the mobileterminal in terms of transmit power efficiency. It is currently aworking assumption for uplink multiple access scheme in 3GPP Long TermEvolution (LTE), or Evolved UTRA.

Methods and devices are described herein relating to simultaneouscommunication over multiple air interfaces (e.g., multiple radiotechnologies each using a different standard, packet format, and/ormodulation scheme). For example, a wireless communication device maycommunicate voice over a first air interface (e.g., 1xRTT) and data onlyover a second air interface (e.g., EVDO, 1xAdvanced, DO (Release 0,Revision A or B), UMTS (HSPA+), GSM, GPRS, and EDGE technologies).1xRTT, also known as 1x, 1xRTT, and IS-2000, is an abbreviation of 1times Radio Transmission Technology. EVDO, abbreviated as EV or DO, isan abbreviation of Evolution-Data Only. Both 1xRTT and EVDO aretelecommunications standards for the wireless transmission of datathrough radio signals maintained by 3GPP2 (3^(rd) Generation PartnershipProject), which are considered types of CDMA2000 (Code Division MultipleAccess 2000).

For clarity, certain aspects of the methods and devices are describedfor an HRPD system that implements IS-856. HRPD is also referred to asCDMA2000 1xEVDO (Evolution-Data Optimized), 1xEV-DO, 1x-DO, DO, HighData Rate (HDR), etc. The terms “HRPD”, “EV-DO”, and “DO” are often usedinterchangeably. HRPD is described in 3GPP2 C.S0024-B, entitled“cdma2000 High Rate Packet Data Air Interface Specification,” datedMarch 2007, which is publicly available. For clarity, HRPD terminologyis used in much of the description below.

The methods and devices described herein may be used for an accessterminal as well as an access point. An access point is generally afixed station that communicates with the access terminals and may alsobe referred to as a base station, a Node B, etc. An access terminal maybe stationary or mobile and may also be referred to as a mobile station,a user equipment (UE), a mobile equipment, a terminal, a subscriberunit, a station, etc. An access terminal may be a cellular phone, apersonal digital assistant (PDA), a handset, a wireless communicationdevice, a handheld device, a wireless modem, a laptop computer, etc. Forclarity, the use of the methods and devices for an access terminal isdescribed below.

The methods and devices herein correspond to the reception andtransmission of one or multiple signals simultaneously. Each signal maybe transmitted using on a different channel using one or more airinterfaces. A channel is a frequency channel for one signal. A channelis also commonly referred to as a carrier.

FIG. 1 is a diagram illustrating wireless communication devices engagedin simultaneous communication over two air interfaces. Each wirelesscommunication device 10 can simultaneously establish a first airinterface 110 and a second air interface 120 between itself and one ormore access points 130. In one embodiment, the first air interface 110is established at a first channel defined by a first frequency orfrequency band, whereas the second air interface 120 is established at asecond channel defined by a second frequency or frequency band which isdifferent from the first frequency or frequency band.

In one embodiment, the first air interface 110 supports 1xRTT trafficand the second air interface 120 supports EVDO traffic. In otherembodiments, the first air interface 110 or the second air interface 120can support 1xAdvanced, DO (Release 0, Revision A or B), UMTS (HSPA+),GSM, GPRS, and EDGE technologies.

FIG. 2 is a functional block diagram of a wireless communication device.The wireless communication device 10 includes a processor 210 in datacommunication with a memory 220, an input device 230, and an outputdevice 240. The processor is further in data communication with atransceiver 260. The transceiver 260 is also in data communication withan antenna 270. Although described separately, it is to be appreciatedthat functional blocks described with respect to the wirelesscommunication device 10 need not be separate structural elements. Forexample, the processor 210 and memory 220 may be embodied in a singlechip. Similarly, two or more of the processor 210, and transceiver 260may be embodied in a single chip.

The processor 210 can be a general purpose processor, a digital signalprocessor (DSP), an application specific integrated circuit (ASIC), afield programmable gate array (FPGA) or other programmable logic device,discrete gate or transistor logic, discrete hardware components, or anysuitable combination thereof designed to perform the functions describedherein. A processor may also be implemented as a combination ofcomputing devices, e.g., a combination of a DSP and a microprocessor, aplurality of microprocessors, one or more microprocessors in conjunctionwith a DSP core, or any other such configuration.

The processor 210 can be coupled, via one or more buses, to readinformation from or write information to memory 220. The processor mayadditionally, or in the alternative, contain memory, such as processorregisters. The memory 220 can include processor cache, including amulti-level hierarchical cache in which different levels have differentcapacities and access speeds. The memory 220 can also include randomaccess memory (RAM), other volatile storage devices, or non-volatilestorage devices. The storage can include hard drives, optical discs,such as compact discs (CDs) or digital video discs (DVDs), flash memory,floppy discs, magnetic tape, and Zip drives.

The processor 210 is also coupled to an input device 230 and an outputdevice 240 for, respectively, receiving input from and providing outputto, a user of the wireless communication device 10. Suitable inputdevices include, but are not limited to, a keyboard, buttons, keys,switches, a pointing device, a mouse, a joystick, a remote control, aninfrared detector, a video camera (possibly coupled with videoprocessing software to, e.g., detect hand gestures or facial gestures),a motion detector, or a microphone (possibly coupled to audio processingsoftware to, e.g., detect voice commands). Suitable output devicesinclude, but are not limited to, visual output devices, includingdisplays and printers, audio output devices, including speakers,headphones, earphones, and alarms, and haptic output devices, includingforce-feedback game controllers and vibrating devices.

The processor 210 is further coupled to a transceiver 260. Thetransceiver 260 may comprise one or more modems. The transceiver 260prepares data generated by the processor 210 for wireless transmissionvia the antenna 270 according to one or more air interface standards.The transceiver 260 also demodulates data received via the antenna 270according to one or more air interface standards. The transceiver caninclude a transmitter, receiver, or both. In other embodiments, thetransmitter and receiver are two separate components. The transceiver260, can be embodied as a general purpose processor, a digital signalprocessor (DSP), an application specific integrated circuit (ASIC), afield programmable gate array (FPGA) or other programmable logic device,discrete gate or transistor logic, discrete hardware components, or anysuitable combination thereof designed to perform the functions describedherein.

It may be desirable to support transmission and/or reception of one ormore signals sent over multiple channels using as little circuitry aspossible in order to reduce cost, lower power consumption, improvereliability, and obtain other benefits. Accordingly, embodiments ofreceivers and transmitters are described herein that employ a single RFreceive chain and a single RF transmit chain, respectively. Each RFchain may be wideband and designed for transmission and reception,respectively, of multiple signals over multiple channels using one ormore air interfaces.

FIG. 3 is a functional block diagram of an exemplary receiver 300 of awireless communication device. FIG. 3 illustrates exemplary componentswhich may be embodied in the transceiver 260 of FIG. 2. The receiver 300may be configured to receive signals over a configurable frequency rangeas discussed below. The receiver 300 includes a single RF receive chain301 and a digital section 302. The digital section 302 is divided into Ndigital process chains 304. Each digital process chain may correspond toa decoding path for a signal sent using a particular type of airinterface. Each air interface may use a different coding scheme andtherefore require different decoding hardware to decode the signal. Twoexemplary paths are described, however, other similar paths may also beprovided in addition to or in place of the described paths. The firstpath 304 a corresponds to the demodulation path for a high data ratesignal, such as a DO signal. The second path 304 n corresponds to thedemodulation path for a voice signal, such as a 1xRTT signal.

The single RF receive chain 301 is configured to receive a signalcomprising multiple signals sent over multiple air interfaces.Accordingly, instead of requiring multiple copies of each component inthe RF receive chain to receive multiple signals over multiple airinterfaces, only a single copy of each component is needed. Further,components of the digital section 302 may also be shared to processmultiple signal received over multiple air interfaces. For example, asingle analog-to-digital converter and a single digital low-pass filtermay be used for processing the multiple signals. This may reduce costand/or complexity of the transceiver 260.

The RF receive chain 301 may implement a super-heterodyne architectureor a direct-conversion architecture. In the super-heterodynearchitecture, a received RF signal is frequency downconverted inmultiple stages, e.g., from RF to an intermediate frequency (IF) in onestage, and then from IF to baseband in another stage. In thedirect-conversion architecture, which is also referred to as a zero-IFarchitecture, the received RF signal is frequency downconverted from RFdirectly to baseband in one stage. The super-heterodyne anddirect-conversion architectures may use different circuit blocks and/orhave different circuit requirements. The following description assumesthe use of the direct-conversion architecture.

A signal is received on the antenna 270 and passed to the RF receivechain 301. The received signal may comprise multiple signals sent overmultiple air interfaces. Within RF receive chain 301, a low noiseamplifier (LNA) 310 may receive and amplify the received signal with again G_(LNA) and provide an amplified RF signal. The gain G_(LNA) becalculated based on the received signal strength (Rx Automatic GainControl (AGC) measured in dB) of each of the multiple signals of thereceived signal. For example, the Rx AGC of a signal may be below athreshold value. The threshold value may be a value sufficient to allowthe signal to be processed. If the Rx AGC of the signal is too low, theG_(LNA) may be increased. In one embodiment, since only one LNA appliesthe same G_(LNA) to multiple signals, the G_(LNA) is based on theweakest signal to make sure the Rx AGC is sufficient for all thesignals. In another embodiment, the G_(LNA) may be based on the weakestsignal as well as additional criteria. For example, the receiver 300 maydetermine if one signal has a signal strength that, if amplified byG_(LNA) based on the weakest signal, would saturate an analog-to-digitalconverter (ADC) 350 of the receiver 300 (i.e., the signal exceeds theinput range of the ADC 350). In order to avoid saturation, the G_(LNA)may be based on another received signal, and the weakest signal may bedropped (e.g., the frequency range that is received may be configured toa range that does not include the weakest signal) or go unused. The RxAGC may be measured for each of the multiple signals using the digitalsection 302 as discussed below.

A bandpass filter 320 may filter the signal from LNA 310 to removeout-of-band signal components and provide an input RF signal. Bandpassfilter 320 may be a surface acoustic wave (SAW) filter, a ceramicfilter, or some other type of filter. A mixer 330 may frequencydownconvert the input RF signal from RF to baseband with an analog localoscillator (LO) signal of a frequency f_(c) from an LO generator. The LOgenerator may include a voltage controlled oscillator (VCO), a phaselocked loop (PLL), a reference oscillator, etc. Optionally, a variablegain amplifier (VGA) may amplify the downconverted signal from mixer 330with a gain G_(VGA). Optionally, a summer may add a coarse DC offsetestimate to remove DC offset in the amplified signal from the VGA. Ananalog lowpass filter 340 may filter the signal and provide an analogbaseband signal to digital section 302.

Within digital section 302, an analog-to-digital converter (ADC) 350 maydigitize the analog baseband signal at a sampling rate of f.sub.ADC andprovide one or more sample streams. The ADC sampling rate may be fixedand selected based on the number and types of air interfaces that can bereceived simultaneously. Alternatively, the ADC sampling rate may beconfigurable and selected based on the number and types of airinterfaces being received. Optionally, a pre-processor may performpre-processing on the one or more sample streams from ADC 350. Thesample streams may then be sent to a digital filter 360. Digital filter360 may filter the sample stream to remove undesired signal components.The sample stream may then be provided to each of the N digital processchains 304 a to 304 n. Digital process chains 304 a and 304 n aredescribed below. The sample stream may comprise data sent using multipleair interfaces.

Digital process chain 304 a receives the sample stream, which maycomprise a first signal sent using a first air interface and one or moreadditional signals. A rotator 370 a may operate as a digitaldowncoverter, frequency downconvert the input sample stream with adigital LO signal, and provide a down converted sample stream of a firstsignal sent using a first air interface. The rotator 370 a may multiplythe input sample stream by a center frequency f₁, which is the centerfrequency channel over which the first signal was transmitted. A digitalfilter 380 a may filter the downconverted sample stream to remove imagescaused by the digital downconversion and other undesired signalcomponents.

The filtered signal may be sent to a receiver front end 385 a, whichprocesses the incoming signal. The front end 385 a may measure the RxAGC of the signal. As discussed above, the Rx AGC of the signal may beused to control the gain G_(LNA) of the LNA 310. The Rx AGC may also beused to determine whether to add or drop frequencies at which signalsare received. For example, if the total power within the frequency rangecurrently received saturates the ADC 350 (i.e., the received signalexceeds the input range of the ADC 350), some signals may be dropped.Signals may be dropped, for example, by configuring the frequency range(e.g., by reducing the range or shifting the range) to not include someof the signals that saturate the ADC 350. For example, some signals maybe preferred over other signals (e.g., voice signals may be preferredover data signals) and therefore non preferred signals may be droppedfirst when determining which signals to drop. Further, the front end 385a may scale the filtered samples to obtain the desired amplitude andprovide an output sample stream to a sample random access memory (RAM)390 a, which temporarily stores the sample stream.

The sample stream may be accessed from sample RAM 390 a by a searcher391 a. The searcher 391 a may be configured to search the sample streamfor pilot signals received over the center frequency f₁. The pilotsignals may be sent by other communication devices such as accesspoints. A pilot signal may comprise a known reference signal fordetermining the strength of signals received from an access point. Theknown reference signal may be compared to the received reference signalto determine signal quality. The strength of signals received from theaccess point may comprise an E_(cp)/I_(o) ratio (energy of the pilotsignal to energy of interfering signals ratio) or a signal-to-noiseratio. The pilot signal may also comprise an offset pseudo noise (PN)short code. The offset PN short code may comprise a code or sequence ofnumbers that identifies the access point and/or the access point type(e.g., femto, macro, pico). The offset PN short code may comprise a PNshort code with a PN offset applied. The PN offset may indicate thedelay from the true network synchronization time applied to a PN shortcode. In one embodiment, all of the access points may use the same PNshort code. However, a different PN offset may be applied to the PNshort code for different access points. Thus, the PN offset directlycorrelates to the offset PN short code and the terms “PN offset” and“offset PN short code” may be used interchangeably herein. Accordingly,by identifying pilot signals with different PN offsets in the samplestream, the searcher 391 a may identify additional access pointstransmitting over the center frequency f₁.

The sample stream may also be accessed from sample RAM 390 a by arake/equalizer receiver 392 comprising a rake receiver and/or anequalizer receiver. The rake/equalizer receiver 392 processes thesignal. A rake receiver may be selected for some operating scenarios(e.g., low SNR) and an equalizer receiver may be selected for otheroperating scenarios (e.g., high SNR and/or high data rate). In general,either a rake receiver or an equalizer receiver may be selecteddepending on which receiver can provide better performance. The signalis then sent to a demodulation symbol buffer 395 a, to buffer the signalfor further processing. The signal is accessed from the buffer by adeinterleaver 396 a, which may deinterleave (or reorder) the symbolestimates in a manner complementary to the interleaving performed by thetransmitter that sent the signal. A decoder 398 a (e.g., a turbodecoder) may decode the deinterleaved symbol estimates and providedecoded data.

Digital process chain 304 n receives the sample stream, which maycomprise a second signal sent using a second air interface and one ormore additional signals. A rotator 370 n may operate as a digitaldowncoverter, frequency downconvert the input sample stream with adigital LO signal, and provide a down converted sample stream of asecond signal sent using a second air interface. The rotator 370 n maymultiply the input sample stream by a center frequency f_(n), which isthe center frequency channel over which the second signal wastransmitted. A digital filter 380 n may filter the downconverted samplestream to remove images caused by the digital downconversion and otherundesired signal components.

The filtered signal may be sent to a receiver front end 385 n, whichprocesses the incoming signal. The front end 385 n may measure the RxAGC of the signal. As discussed above, the Rx AGC of the signal may beused to control the gain G_(LNA) of the LNA 310. Further, the front end385 n may scale the filtered samples to obtain the desired amplitude andprovide an output sample stream to a sample random access memory (RAM)390 n, which temporarily stores the sample stream.

The sample stream may be accessed from sample RAM 390 n by a searcher391 n. The searcher 391 n may be configured to search the sample streamfor pilot signals received over the center frequency f_(n). Byidentifying pilot signals with different PN offsets in the samplestream, the searcher 391 n may identify additional access pointstransmitting over the center frequency f_(n).

The sample stream may also be accessed from sample RAM 390 n by a CDMAdemodulator 393. The CDMA demodulator 393 demodulates the incoming CDMAstream into symbols as is known in the art. The signal is then sent to ademodulation symbol buffer 395 n, to buffer the signal for furtherprocessing. The signal is accessed from the buffer by a deinterleaver396 n, which may deinterleave (or reorder) the symbol estimates in amanner complementary to the interleaving performed by the transmitterthat sent the signal. A decoder 398 n (e.g., a viterbi decoder) maydecode the deinterleaved symbol estimates and provide decoded data. Ingeneral, the processing by receiver 300 for each received signal isdependent on the processing performed for the received signal by thetransmitter or access point. Receiver 300 may be used in conjunctionwith one or more transmitters that can transmit using one or more airinterfaces.

ADC 350 may be implemented with a delta-sigma (ΔΣ) ADC that canspectrally shape quantization noise such that the noise is pushed fromlow frequencies toward higher frequencies. This noise shaping may allowthe received signals to observe less quantization noise inband and henceachieve higher signal-to-noise ratios (SNRs). The out-of-bandquantization noise may be more easily filtered by subsequent digitalfilters. The noise spectrum of the ΔΣ ADC may be determined by anoversampling ratio (OSR), which is the ratio of the sampling rate of theΔΣ ADC to the two-sided bandwidth of the received signals beingdigitized. In general, a higher sampling rate may push the quantizationnoise higher in frequency, increase the bandwidth of the ΔΣ ADC, andimprove SNR. However, the higher sampling rate may also result in higherpower consumption. The sampling rate may be varied based on variousfactors such as the number of signals being received, the operatingconditions (e.g., the desired signal level and undesired signal level),power consumption consideration, etc.

The ΔΣ ADC may use a reference voltage V_(ref) for making approximationsof changes in the analog baseband signal amplitude. This V_(ref) voltagemay determine the maximum signal level that can be captured by the ΔΣADC without clipping, which is often called the full-scale level. TheV_(ref) voltage may also determine the quantization noise, which istypically given relative to the V_(ref) voltage. The V_(ref) voltage maybe varied based on various factors such as the number of signals beingreceived, the signal level, the undesired signal level, etc. Forexample, the V_(ref) voltage may be reduced when receiving multiplesignals, when the signal level is low, etc. The lower V_(ref) voltagemay lower the quantization noise level and improve SNR for the scenariosdescribed above. However, the noise floor of the ΔΣ ADC may come intoplay and become the limiting factor as the quantization noise level isdropped.

In general, wider bandwidth may be achieved for the ΔΣ ADC by increasingthe sampling rate and/or lowering the V_(ref) voltage. The widerbandwidth may accommodate reception of multiple signals simultaneously.

Rake/equalizer receiver 392 may comprise a rake receiver and/or anequalizer receiver. The rake receiver may process the output samplestream for a first signal for one or more signal paths (or multipaths)detected for the first signal. The rake receiver may perform variousfunctions such as despreading with a complex pseudo-random number (PN)sequence used by an access point, decovering with Walsh codes used fordata, pilot and overhead channels, pilot estimation, coherentdemodulation of the decovered symbols with pilot estimates, symbolcombining across the multipaths, etc. The equalizer receiver may processthe output sample stream for the first signal. The dqualizer receivermay perform various functions such as pilot estimation,derivation/adaptation of filter coefficients, filtering of the outputsamples with the filter coefficients, despreading with the complex PNsequence, decovering with the Walsh codes, symbol scaling, etc.

FIG. 3 illustrates one embodiment of the RF receive chain 301. Ingeneral, an RF receive chain may include one or more stages ofamplifier, filter, mixer, etc. These circuit blocks may be arrangeddifferently from the configuration shown in FIG. 3. An RF receive chainmay also include different and/or additional circuit blocks not shown inFIG. 3. All or a portion of RF receive chain 301 may be implemented onone or more RF integrated circuits (RFICs), mixed-signal ICs, etc. Forexample, LNA 310, mixer 330, and analog lowpass filter 340 may beimplemented on an RFIC, e.g., an RF receiver (RFR) or an RFtransmitter/receiver (RTR) chip.

Although described separately, it is to be appreciated that functionalblocks described with respect to the receiver 300 need not be separatestructural elements. For example, one or more components may be embodiedin a single chip. One or more of the functional blocks and/or one ormore combinations of the functional blocks described with respect to thereceiver 300 may be embodied as a general purpose processor, a digitalsignal processor (DSP), an application specific integrated circuit(ASIC), a field programmable gate array (FPGA) or other programmablelogic device, discrete gate or transistor logic, discrete hardwarecomponents, or any suitable combination thereof designed to perform thefunctions described herein. One or more of the functional blocks and/orone or more combinations of the functional blocks described with respectto the receiver 300 may also be implemented as a combination ofcomputing devices, e.g., a combination of a DSP and a microprocessor, aplurality of microprocessors, one or more microprocessors in conjunctionwith a DSP communication, or any other such configuration.

FIG. 4 is a functional block diagram of an exemplary transmitter 400 ofa wireless communication device. FIG. 4 illustrates exemplary componentswhich may be embodied in the transceiver 260 of FIG. 2. The function ofthe transmitter is similar to that of the receiver, but in reverse. Thetransmitter 400 includes a digital section 401 and a RF transmit chain402. The digital section 401 is divided into N digital process chains404. Each digital process chain may correspond to an encoding path for asignal to be transmitted using a particular type of air interface. Eachair interface may use a different coding scheme and therefore requiredifferent encoding hardware to encode the signal. Two exemplary pathsare described, however, other similar paths may also be provided inaddition to or in place of the described paths. The first path 404 acorresponds to the encoding path for a high data rate signal, such as aDO signal. The second path 404 n corresponds to the encoding path for avoice signal, such as a 1xRTT signal.

The single RF transmit chain 402 is configured to transmit a signalcomprising multiple signals sent over multiple air interfaces.Accordingly, instead of requiring multiple copies of each component inthe RF transmit chain to receive multiple signals over multiple airinterfaces, only a single copy of each component is needed. Further,components of the digital section 401 may also be shared to processmultiple signal received over multiple air interfaces. For example, asingle digital-to-analog converter, a single encoder RAM, and a singlePN spreader may be used for processing the multiple signals. This mayreduce cost and/or complexity of the transceiver 260.

Within digital section 401, an encoder random access memory (RAM) 405holds the digital data to be encoded and transmitted. The first path 404a may include an DO encoder 406 a that encodes a first set of data intoDO symbols. The encoded data is then passed to a DO interleaver 408 a,which orders the symbols by methods known in the art. Similarly, thesecond path 404 n may include a CDMA encoder 406 n that encodes a secondset of data into CDMA symbols. The encoded data is then passed to a CDMAinterleaver 408 n, which orders the symbols by methods known in the art.Both the data streams are then passed to a pseudo noise (PN) spreader410. PN spreader spreads each of the input sequences in accordance withone or more PN sequences as known in the art. The PN spreader providesthe first set of encoded data to the digital filter 412 a and the secondset of encoded data to the digital filter 412 n. Each digital filter 412may filter its input symbols, perform upsampling, and provide a filteredsample stream to a rotator 414. Each rotator 414 operates as a digitalupconverter, frequency upconverts its filtered sample stream with adigital local oscillator (LO) signal, and provided an upconverted samplestream. Each rotator 414 may multiply the input sample stream by acenter frequency f₁ to f_(n). For example, the first set of encoded datamay be multiplied by a frequency f₁ and the second set of encoded datamay be multiplied by a frequency f_(n). The frequency may be determinedby the air interface and/or the carrier frequency that is used totransmit the signal. Each signal is then input to a summer 416 that sumsthe N upconverted sample streams from each rotator 414. The summedsignal is then passed to a digital-to-analog converter (DAC) 420, whichconverts the sample stream to analog and provided an analog basebandsignal comprising the N signals. The analog baseband signal is then sentto the RF transmit chain 402.

The RF transmit chain 402 may implement a super-heterodyne architectureor a direct-conversion architecture. In the super-heterodynearchitecture, a baseband signal is frequency upconverted in multiplestages, e.g., from baseband to an intermediate frequency (IF) in onestage, and then from IF to RF in another stage. In the directconversionarchitecture, which is also referred to as a zero-IF architecture, thebaseband signal is frequency upconverted from baseband directly to RF inone stage. The superheterodyne and direct-conversion architectures mayuse different circuit blocks and/or have different circuit requirements.The following description assumes the use of the direct-conversionarchitecture.

Within RF transmit chain 402, an analog lowpass filter 422 filters theanalog baseband signal from DAC 420 to remove images caused by thedigital-to-analog conversion and provides a filtered signal. A mixer 424frequency upconverts the filtered signal from baseband to RF with ananalog LO signal from an LO generator. The LO generator may include avoltage controlled oscillator (VCO), a phase locked loop (PLL), areference oscillator, etc. Optionally, a variable gain amplifier (VGA)amplifies the upconverted signal from mixer 424 with a variable gain. Abandpass filter 430 filters the signal to remove images caused by thefrequency upconversion. Bandpass filter 430 may be a surface acousticwave (SAW) filter, a ceramic filter, or some other type of filter. Apower amplifier (PA) 432 amplifies the signal from filter 430 andprovides an RF output signal having the proper power level. The RFoutput signal is transmitted via the antenna 270.

DAC 420 and RF transmit chain 402 may be wideband to supportsimultaneous transmission of multiple signals using multiple airinterfaces. DAC 420 may be operated at a sufficiently high clock rateand may have sufficient resolution for conversion of a digital samplestream containing all N signals. Analog lowpass filter 422 may have afixed or variable bandwidth that may be sufficiently wide to pass all ofthe signals being sent simultaneously. The subsequent analog circuitblocks may also be wideband to pass all of the signals. Bandpass filter430 may be wideband and may pass an entire frequency band, e.g., from824 to 849 MHz for cellular band and from 1850 to 1910 MHz for PersonalCommunications Service (PCS) band.

FIG. 4 illustrates one embodiment of RF transmit chain 402. In general,an RF transmit chain may include one or more stages of amplifier,filter, mixer, etc. These circuit blocks may be arranged differentlyfrom the configuration shown in FIG. 4. An RF transmit chain may alsoinclude different and/or additional circuit blocks not shown in FIG. 4.All or a portion of RF transmit chain 402 may be implemented on one ormore RF integrated circuits (RFICs), mixed-signal ICs, etc. For example,analog lowpass filter 422 and mixer 424 may be implemented on an RFIC,e.g., an RF transmitter (RFT) or an RF transmitter/receiver (RTR) chip.

Although described separately, it is to be appreciated that functionalblocks described with respect to the transmitter 400 need not beseparate structural elements. For example, one or more components may beembodied in a single chip. One or more of the functional blocks and/orone or more combinations of the functional blocks described with respectto the transmitter 400 may be embodied as a general purpose processor, adigital signal processor (DSP), an application specific integratedcircuit (ASIC), a field programmable gate array (FPGA) or otherprogrammable logic device, discrete gate or transistor logic, discretehardware components, or any suitable combination thereof designed toperform the functions described herein. One or more of the functionalblocks and/or one or more combinations of the functional blocksdescribed with respect to the transmitter 400 may also be implemented asa combination of computing devices, e.g., a combination of a DSP and amicroprocessor, a plurality of microprocessors, one or moremicroprocessors in conjunction with a DSP communication, or any othersuch configuration.

The embodiments of transceiver 260 as shown in FIGS. 3 and 4 allow formany components to be shared for the processing of multiple signalsreceived and/or transmitted over multiple air interfaces. Accordingly,the cost of producing transceivers that communicate over multiple airinterfaces such as transceiver 260 may be reduced as fewer componentsare necessary. This may also decrease complexity and power consumptionof the transceiver 260.

FIG. 5 illustrates an exemplary process of receiving signals overmultiple air interfaces using a receiver as shown in FIG. 3. The process500 starts at a step 510 where the receiver receives a combined signalcomprising multiple signals sent over multiple air interfaces. Theprocess continues to a step 513 where the gain of the combined signalcomprising the multiple signals is adjusted using a single amplifier. Inone embodiment, the gain may be adjusted based on the weakest of themultiple signals as discussed above. Further, the gain may be adjustedbased on certain rules such as not amplifying the combined signal to alevel that would saturate an ADC of the receiver. Next at a step 515,the combined signal is processed by a single RF chain in the analogdomain. Further at a step 520, the combined signal is converted to thedigital domain by a single ADC. Continuing at a step 525, the combinedsignal is separated into one or more signals; each signal representing asignal sent using a particular air interface.

Next, at a step 530 the receiver determines whether to decode one ormore of the signals. If the receiver determines to decode one or more ofthe signals, the process 500 continues to step 535 where each of the oneor more signals that is to be decoded is decoded using a differentdigital process chain. Continuing at a step 540, the receiver determineswhether to search for pilot signals on one or more of the signals. Ifthe receiver determines to search for pilot signals on one or more ofthe signals, the process continues to step 545 where each of the one ormore signals that is to be searched is searched using a differentsearcher of a different digital process chain. Further at a step 550,the receiver determines whether to measure the Rx AGC of one or more ofthe signals. If the receiver determines to measure the Rx AGC of one ormore of the signals, the process 500 continues to step 555 where each ofthe one or more signals for which the Rx AGC is to be measured ismeasured using a different digital process chain.

FIG. 6 illustrates an exemplary process of transmitting signals overmultiple air interfaces using the transmitter as shown in FIG. 3. Theprocess 600 starts at a step 610 where the transmitter stores multiplesignals to be sent over multiple air interfaces in a single memorylocation. Continuing at a step 615, the multiple signals are separatelyencoded in the digital domain by separate encoders. Further, at a step620, a single PN spreader prepares the multiple signals fortransmission. Next, at a step 625, the multiple signals are combinedinto a combined signal. At a further step 630, the combined signal isconverted to the analog domain by a single DAC. At a next step 635, thecombined signal is processed by a single RF chain and transmitted as asingle combined signal.

FIG. 7 illustrates an exemplary transmission of multiple (N) signalsusing one or more air interfaces. The transmission 700 may comprise Nfrequency channels. Channel 0 has a carrier frequency of f_(ch0),Channel 1 has a carrier frequency of f_(ch1), and so on, and channel Nhas a carrier frequency of f_(chN). The carrier frequencies aretypically selected such that the channels are spaced sufficiently farapart to reduce inter-channel interference. In general, the carrierfrequencies of the N channels may or may not be related to one another.The carrier frequency of each channel may be selected independentlysubject to a minimum inter-channel spacing criterion. The carrierfrequencies may be evenly spaced across frequency and separated by afixed frequency spacing f_(spacing), which may be 1.2288 MHz or someother value. The N signals may carry any type of data for any servicesuch as voice, video, packet data, text messaging, etc. The N signalsmay be received from one or multiple access points and may be receivedat different power levels or at the same power level (as shown in FIG.7). For example, Channels 0 and 3 each use a DO air interface, whileChannel 1 uses a 1xRTT air interface. The transmission may be generatedby the transmitter 400 of FIG. 4, and received by the receiver 300 ofFIG. 3, as described above.

Transceiver 260 may be configured for wideband communications. Forexample, transceiver 260 may be able to simultaneously transmit and/orreceive (TX/RX) signals over a frequency range of 100 MHz as shown inFIG. 8. The frequency range may be dependent on the components used forthe transceiver 260, such as the design of the ADC 350 and the DAC 420of FIGS. 3 and 4. The exact frequency channels that the transceiver 260may TX/RX signals over may be defined by the frequency range and a“center” frequency. The center frequency may be the center frequency ofthe frequency range over which the transceiver 260 TX/RX signals. Forexample, the transceiver 260 may TX/RX signals centered at a frequencyof 100 MHz. The frequency range may be 50 MHz. Accordingly, thetransceiver 260 may TX/RX signals between 75 MHz to 125 MHz.“Recentering” the transceiver 260 refers to choosing a new centerfrequency for the transceiver 260. The center frequency may be set bythe mixer 330 of FIG. 3 for received signals, and the mixer 424 of FIG.4 for transmitted signals.

Accordingly, transceiver 260 may TX/RX signals over channels 1, 2, 3, 4and 5, when the transceiver is set to encode/decode signals centered atfrequency f₁. As shown in FIG. 8, transceiver 260 simultaneously TXs/RXsDO signals over channels 1 and 3. However, to optimize thesignal-to-intereference-plus-noise ratio (SINR) for each channel,transceiver 260 may be set or recentered to encode/decode signalscentered at frequency f₂. In addition, transceiver 260 may need to TX/RXa signal over channel 0, but may not be able to TX/RX signals overchannel 0 when centered at f₁ because it is outside of the 100 MHzfrequency range (f₁−50 MHz to f₁+50 MHz). Accordingly, the transceiver260 may be set or recentered to encode/decode signals centered atfrequency f₃. The recentering of the transceiver 260 may cause datapacket errors or loss of voice data. Accordingly, methods of recenteringthat minimize the impact on the signals transmitted and/or received aredescribed herein.

FIG. 9 is a flowchart of an exemplary process of “recentering” thetransceiver shown in FIG. 2. The process 900 starts at a step 905 wherethe transceiver 260 receives data (e.g., voice communication and/or dataonly communication) over one or more channels using one or more airinterfaces from one or more transmitters. The transceiver 260 is“centered” at a frequency F1. At a next step 910, the transceiver 260transmits a message to each transmitter it is currently receiving datafrom, the message indicating for the one or more transmitters to stoptransmitting for a period of time to the transceiver 260. Further at astep 915, the transceiver 260 recenters to a frequency F2 during thetime period reserved. Continuing at a step 920, the transceiver 260,centered at the frequency F2, receives data over one or more channelsusing one or more air interfaces from one or more transmitters.Accordingly, no communication is lost during the recentering as nocommunication is sent to the transceiver 260 during the recenteringperiod.

In another embodiment, the transceiver 260 may indicate in the messageto stop transmitting at step 910. Further, at an optional step afterstep 915, the transceiver 260 may send another message to each of theone or more transmitters indicating for the one or more transmitters toresume transmitting to the transceiver 260.

In certain embodiments, recentering may or may not be performed based oncertain criteria when not necessary to TX/RX a new channel. For example,wireless communication device 10 may evaluate the benefit of recenteringthe transceiver 260 in terms of SINR of each channel over whichtransceiver 260 TXs/RXs. The wireless communication device 10 mayfurther evaluate throughput and voice quality versus the transient SINRdip from recentering.

One criterion may include determining in what format the data is beingtransmitted and/or received. For example, if the data is transmittedusing a transmission control protocol (TCP), the wireless communicationdevice 10 may not recenter the transceiver 260 since packet errorsduring TCP data transfers may cause throughput back off. If the data istransmitted using a user datagram protocol (UDP), the wirelesscommunication device 10 may recenter the transceiver 260.

A second criterion may include determining if longer packet formats arebeing used for data being transmitted and/or received. If longer packetformats are being used, recentering the transceiver 260 may be performedas transient dips may have less of a probability of causing packeterrors due to the time diversity of long packet formats.

A third criterion may include determining if the signals received overthe one or more channels already have SINRs above a threshold. If theSINRs are above a threshold, the transceiver 260 may not be recenteredas the appropriate SINR level is already attained.

A fourth criterion may include determining whether the residual sideband (RSB) of a given signal can be reduced by recentering thetransceiver 260. The RSB of each of the received signals is thereflection of the signal across the center frequency (e.g., the RSB of asignal received at center frequency+5 MHz will be centered at centerfrequency−5 MHz). For example, two signals may be received at thetransceiver 260. Each of the signals may be received at a frequencyequidistant from the center frequency and on opposite sides of thecenter frequency (e.g., center frequency±5 MHz). Accordingly, the RSB ofeach signal may interfere with the other received signal. Accordingly,the center frequency may be shifted (e.g., by 1.25 MHz) so that the RSBsof the received signals no longer interfere with the received signals.The amount to shift the center frequency may be calculated by scanningadditional frequencies for additional signals and their RSBs to ensurethat interference is reduced at that new center frequency. Thetransceiver 260 may incrementally search other frequency carriers (e.g.,every 1 MHz).

It is to be recognized that depending on the embodiment, certain acts orevents of any of the methods described herein can be performed in adifferent sequence, may be added, merged, or left out all together(e.g., not all described acts or events are necessary for the practiceof the method). Moreover, in certain embodiments, acts or events may beperformed concurrently, e.g., through multi-threaded processing,interrupt processing, or multiple processors, rather than sequentially.

The functionality described herein (e.g., with regard to one or more ofthe accompanying figures) may correspond in some aspects to similarlydesignated “means for” functionality in the appended claims. Referringto FIGS. 10 and 11, the receiver is represented as a series ofinterrelated functional modules.

FIG. 10 is a functional block diagram of another exemplary receiver of awireless communication device as shown in FIG. 2. As shown, the receiver300 may comprise a receiving unit 1005, a converting unit 1010, and aseparating unit 1015. The receiving unit 1005 may correspond at least insome aspects to, for example, an antenna as discussed herein. Theconverting unit 1010 may correspond at least in some aspects to, forexample, an ADC as discussed herein. The separation unit 1015 maycorrespond at least in some aspects to, for example, at least onerotator as discussed herein.

FIG. 11 is a functional block diagram of another exemplary transmitterof a wireless communication device as shown in FIG. 2. As shown, thetransmitter 400 may comprise a combining unit 1105, a converting unit1110, and a transmitting unit 1115. The combining unit 1105 maycorrespond at least in some aspects to, for example, a summer asdiscussed herein. The converting unit 1110 may correspond at least insome aspects to, for example, a DAC as discussed herein. Thetransmitting unit 1115 may correspond at least in some aspects to, forexample, an antenna as discussed herein.

The functionality of the modules of FIGS. 10 and 11 may be implementedin various ways consistent with the teachings herein. In some aspectsthe functionality of these modules may be implemented as one or moreelectrical components. In some aspects the functionality of these blocksmay be implemented as a processing system including one or moreprocessor components. In some aspects the functionality of these modulesmay be implemented using, for example, at least a portion of one or moreintegrated circuits (e.g., an ASIC). As discussed herein, an integratedcircuit may include a processor, software, other related components, orsome combination thereof. The functionality of these modules also may beimplemented in some other manner as taught herein.

It should be understood that any reference to an element herein using adesignation such as “first,” “second,” and so forth does not generallylimit the quantity or order of those elements. Rather, thesedesignations may be used herein as a convenient method of distinguishingbetween two or more elements or instances of an element. Thus, areference to first and second elements does not mean that only twoelements may be employed there or that the first element must precedethe second element in some manner. Also, unless stated otherwise a setof elements may comprise one or more elements. In addition, terminologyof the form “at least one of: A, B, or C” used in the description or theclaims means “A or B or C or any combination of these elements.”

While the specification describes particular examples of the presentinvention, those of ordinary skill can devise variations of the presentinvention without departing from the inventive concept. For example, theteachings herein refer to networks with femto cells and macro cells butare equally applicable to networks with other topologies.

Those skilled in the art will understand that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

Those skilled in the art will further appreciate that the variousillustrative logical blocks, modules, circuits, methods and algorithmsdescribed in connection with the examples disclosed herein may beimplemented as electronic hardware, computer software, or combinationsof both. To clearly illustrate this interchangeability of hardware andsoftware, various illustrative components, blocks, modules, circuits,methods and algorithms have been described above generally in terms oftheir functionality. Whether such functionality is implemented ashardware or software depends upon the particular application and designconstraints imposed on the overall system. Skilled artisans mayimplement the described functionality in varying ways for eachparticular application, but such implementation decisions should not beinterpreted as causing a departure from the scope of the presentinvention.

The various illustrative logical blocks, modules, and circuits describedin connection with the examples disclosed herein may be implemented orperformed with a general purpose processor, a digital signal processor(DSP), an application specific integrated circuit (ASIC), a fieldprogrammable gate array (FPGA) or other programmable logic device,discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described herein.A general-purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP communication, or anyother such configuration.

The methods or algorithms described in connection with the examplesdisclosed herein may be embodied directly in hardware, in a softwaremodule executed by a processor, or in a combination of the two. Asoftware module may reside in RAM memory, flash memory, ROM memory,EPROM memory, EEPROM memory, registers, hard disk, a removable disk, aCD-ROM, or any other form of storage medium known in the art. A storagemedium may be coupled to the processor such that the processor may readinformation from, and write information to, the storage medium. In thealternative, the storage medium may be integral to the processor. Theprocessor and the storage medium may reside in an ASIC.

In one or more exemplary embodiments, the functions described may beimplemented in hardware, software, firmware, or any combination thereof.If implemented in software, the functions may be stored on ortransmitted over as one or more instructions or code on acomputer-readable medium. Computer-readable media includes both computerstorage media and communication media including any medium thatfacilitates transfer of a computer program from one place to another. Astorage media may be any available media that can be accessed by ageneral purpose or special purpose computer. By way of example, and notlimitation, such computer-readable media may comprise RAM, ROM, EEPROM,CD-ROM or other optical disk storage, magnetic disk storage or othermagnetic storage devices, or any other medium that may be used to carryor store desired program code means in the form of instructions or datastructures and that can be accessed by a general-purpose orspecial-purpose computer, or a general-purpose or special-purposeprocessor. Also, any connection is properly termed a computer-readablemedium. For example, if the software is transmitted from a website,server, or other remote source using a coaxial cable, fiber optic cable,twisted pair, digital subscriber line (DSL), or wireless technologiessuch as infrared, radio, and microwave, then the coaxial cable, fiberoptic cable, twisted pair, DSL, or wireless technologies such asinfrared, radio, and microwave are included in the definition of medium.Disk and disc, as used herein, includes compact disc (CD), laser disc,optical disc, digital versatile disc (DVD), floppy disk and blu-ray discwhere disks usually reproduce data magnetically, while discs reproducedata optically with lasers. Combinations of the above should also beincluded within the scope of computer-readable media.

The previous description of the disclosed examples is provided to enableany person skilled in the art to make or use the present invention.Various modifications to these examples will be readily apparent tothose skilled in the art, and the generic principles defined herein maybe applied to other examples without departing from the spirit or scopeof the invention. Thus, the present invention is not intended to belimited to the examples shown herein but is to be accorded the widestscope consistent with the principles and novel features disclosedherein.

What is claimed is:
 1. A method comprising: receiving, at a receiver, afirst input within a first frequency range centered at a first centerfrequency during a first time period, the first input comprising a firstsignal and a second signal, wherein the first signal is encoded using afirst radio technology and the second signal is encoded using a secondradio technology; separating the first input into the first signal andthe second signal; transmitting a first message to a source of the firstsignal and the second signal, the first message indicative of a secondtime period during which the source is not to transmit to the receiver;recentering the receiver to receive a second input within a secondfrequency range centered at a second center frequency, whereinrecentering the receiver is based on a set of criteria; and wherein theset of criteria comprises a first criterion, the first criterioncorresponding to whether a signal-to-interference-plus-noise ratio(SINR) of the first signal received within the first frequency range isabove a threshold SINR, a SINR of the second signal received within thefirst frequency range is above the threshold SINR, or a combinationthereof; transmitting a second message to the source, the second messageindicative of a third time period during which the source is to transmitto the receiver; and receiving, at the receiver from the source, thesecond input within the second frequency range during the third timeperiod, wherein the third time period is after the second time period.2. The method of claim 1, further comprising converting the first inputvia a single analog-to-digital converter.
 3. The method of claim 1,wherein receiving the first input comprises receiving the first inputvia a single radio frequency (RF) chain.
 4. The method of claim 3,further comprising processing the first signal using a first digitaldecoding path, and processing the second signal using a second digitaldecoding path.
 5. The method of claim 4, wherein the first signal iscentered at a first signal frequency and the second signal is centeredat a second signal frequency, and wherein the first signal frequency andthe second signal frequency are within the first frequency range.
 6. Themethod of claim 4, further comprising decoding the first signal, thesecond signal, or a combination thereof.
 7. The method of claim 4,further comprising searching for pilot signals on the first signal, thesecond signal, or a combination thereof.
 8. The method of claim 4,further comprising determining a signal strength of the first signal, asignal strength of the second signal, or a combination thereof.
 9. Themethod of claim 8, further comprising adjusting an amplification levelof the first input based on the signal strength of the first signal, thesignal strength of the second signal, or a combination thereof.
 10. Themethod of claim 1, wherein the second input comprises a previous signaland a third signal, wherein the previous signal includes the firstsignal or the second signal, wherein the third signal is centered at athird signal frequency, wherein at least one of the first signal and thesecond signal is within the second frequency range, and wherein thethird signal is within the second frequency range.
 11. The method ofclaim 1, further comprising performing the recentering operation basedon a signal strength of the first signal, a signal strength of thesecond signal, or a combination thereof.
 12. The method of claim 1,wherein the set of criteria further comprises a second criterion, thesecond criterion corresponding to whether the received first signalcomplies with a protocol, whether the received second signal complieswith the protocol, whether a signal to be transmitted complies with theprotocol, or a combination thereof.
 13. The method of claim 12, whereinthe protocol is a user datagram protocol (UDP).
 14. The method of claim1, wherein the set of criteria further comprises a third criterion, thethird criterion corresponding to whether the received first signalcomplies with a packet format, whether the received second signalcomplies with the packet format, whether a signal to be transmittedcomplies with the packet format, or a combination thereof.
 15. Themethod of claim 1, wherein the first radio technology comprises a voiceair interface and the second radio technology comprises a data only airinterface.
 16. The method of claim 1, wherein a standard, a packetformat, a modulation scheme, or a combination thereof of the first radiotechnology is different than a corresponding standard, a correspondingpacket format, a corresponding modulation scheme, or a combinationthereof of the second radio technology.
 17. The method of claim 1,wherein receiving the first input comprises receiving the first input ata mobile device from a base station.
 18. A method comprising: combininga first signal and a second signal, wherein the first signal is encodedusing a first radio technology and the second signal is encoded using asecond radio technology; transmitting the combined signal to a receiver;receiving, in response to a recentering operation that is performedbased on a criterion corresponding to whether asignal-to-interference-plus-noise (SINR) of the first signal receivedover a first frequency range is above a threshold SINR, a SINR of thesecond signal received within the first frequency range is above thethreshold SINR, or a combination thereof, a first message indicative ofa first time period during which to refrain from transmitting to thereceiver; receiving a second message indicative of a second time periodduring which to transmit to the receiver; and transmitting a secondcombined signal to the receiver during the second time period, whereinthe second time period is after the first time period.
 19. The method ofclaim 18, wherein the first radio technology comprises a voice airinterface and the second radio technology comprises a data only airinterface.
 20. The method of claim 18, wherein encoding the first signalcomprises encoding the first signal using a first digital encoding pathand encoding the second signal comprises encoding the second signalusing a second digital encoding path.
 21. The method of claim 18,further comprising converting the combined signal via a singledigital-to-analog converter.
 22. The method of claim 18, furthercomprising processing the combined signal using a single RF chain.
 23. Awireless apparatus comprising: a summer configured to combine a firstsignal and a second signal, wherein the first signal is encoded using afirst radio technology and the second signal is encoded using a secondradio technology; and a transceiver configured to: transmit the combinedsignal to a receiver; receive, in response to a recentering operationthat is performed based on a criterion that corresponds to whether asignal-to-interference-plus-noise (SINR) of the first signal receivedover a first frequency range is above a threshold SINR, a SINR of thesecond signal received within the first frequency range is above thethreshold SINR, or a combination thereof, a first message indicative ofa first time period during which to refrain from transmitting to thereceiver; receive a second message indicative of a second time periodduring which to transmit to the receiver; and transmit a second combinedsignal to the receiver during the second time period, wherein the secondtime period is after the first time period.
 24. A wireless apparatuscomprising: means for receiving, wherein the means for receiving isconfigured to: receive from a source a first input within a firstfrequency range centered at a first center frequency during a first timeperiod, the first input comprising a first signal and a second signal,wherein the first signal is encoded using a first radio technology andthe second signal is encoded using a second radio technology; andreceive from the source a second input within a second frequency rangeduring a third time period and wherein the third time period is after asecond time period; means for separating the first input into the firstsignal and the second signal; means for transmitting, wherein the meansfor transmitting is configured to: transmit a first message to thesource, the first message indicative of the second time period duringwhich the source is not to transmit to the means for receiving; andtransmit a second message to the source, the second message indicativeof the third time period during which the source is to transmit to themeans for receiving; and means for recentering the means for receivingto receive the second input within the second frequency range centeredat a second center frequency, wherein recentering the means forreceiving is based on a set of criteria; and wherein the set of criteriacomprises a first criterion, the first criterion corresponding towhether a signal-to-interference-plus-noise ratio (SINR) of the firstsignal received within the first frequency range is above a thresholdSINR, a SINR of the second signal received within the first frequencyrange is above the threshold SINR, or a combination thereof.
 25. Ainstructions that, when executed by a computer, cause the computer tonon-transitory computer-readable medium comprising: combine a firstsignal and a second signal, wherein the first signal is encoded using afirst radio technology and the second signal is encoded using a secondradio technology; transmit the combined signal to a receiver; receive,in response to a recentering operation that is performed based on acriterion that corresponds to whether asignal-to-interference-plus-noise (SINR) of the first signal receivedover a first frequency range is above a threshold SINR, a SINR of thesecond signal received within the first frequency range is above thethreshold SINR, or a combination thereof, a first message indicative ofa first time period during which to refrain from transmitting to thereceiver; receive a second message indicative of a second time periodduring which to transmit to the receiver; and transmit a second combinedsignal to the receiver during the second time period, wherein the secondtime period is after the first time period.
 26. A method comprising:receiving, at a receiver, a first input within a first frequency rangecentered at a first center frequency during a first time period, thefirst input comprising a first signal and a second signal, wherein thefirst signal is encoded using a first radio technology and the secondsignal is encoded using a second radio technology; separating the firstinput into the first signal and the second signal; transmitting a firstmessage to a source of the first signal and the second signal, the firstmessage indicative of a second time period during which the source isnot to transmit to the receiver; recentering the receiver to receive asecond input within a second frequency range centered at a second centerfrequency, wherein recentering the receiver is based on a set ofcriteria, and wherein the set of criteria comprises a first criterion,the first criterion corresponding to whether a residual side band (RSB)of the first signal is likely to cause interference with the firstsignal, whether a RSB of the second signal is likely to causeinterference with the second signal, or a combination thereof;transmitting a second message to the source, the second messageindicative of a third time period during which the source is to transmitto the receiver; and receiving, at the receiver from the source, thesecond input within the second frequency range during the third timeperiod, wherein the third time period is after the second time period.27. A wireless apparatus comprising: means for combining a first signaland a second signal, wherein the first signal is encoded using a firstradio technology and the second signal is encoded using a second radiotechnology; means for transmitting the combined signal to a receiver;and means for receiving a first message indicative of a first timeperiod during which to refrain from transmitting to the receiver, thefirst message in response to a recentering operation that is performedbased on a criterion that corresponds to whether asignal-to-interference-plus-noise (SINR) of the first signal receivedover a first frequency range is above a threshold SINR, a SINR of thesecond signal received within the first frequency range is above thethreshold SINR, or a combination thereof, the means for receivingfurther for receiving a second message indicative of a second timeperiod during which to transmit to the receiver; and the means fortransmitting further for transmitting a second combined signal to thereceiver during the second time period, wherein the second time periodis after the first time period.